Natural History Aspects of Christmas
A Comet Hale-Bopp photograph taken in 2000 by Maurice Clark
A comet like this may have been the Star of Bethlehem
At this time of year Christians celebrate the birth of the man who has come to be known as their savior, Jesus. Some aspects of this historical and religious episode are reflected in natural history and I recount a few here.
First, of course, is the fact that our calendar dates from the time of this event. For example, in a few days we will complete the 2009th year since Jesus' birthday. These years are often formally designated AD for Anno Domine, meaning year of our lord, or CE for Common Era. BC for Before Christ or BCE for Before the Common Era are used for earlier dates.
Well, not quite. The beginning year, one (only a few astronomers consider a year zero), was established by the monk Dionysius Exiguus over 500 years after Jesus was born. How he hit upon this date is not known but he clearly was in error for King Herod, the villain in the story of Jesus' birth, died a few years earlier.
According to the Biblical Gospel of Matthew an astronomical event now known as the Star of Bethlehem or the Christmas Star led wise men from the east to worship this newborn "king of the Jews." Astronomers have calculated various episodes that took place at about that time, among them: conjugations (close approaches) of Venus and Jupiter in 3 and 2 BC and Jupiter and Regulus in 2 BC, and Halley's comet in 12 BC. A better bet is probably another comet in 5 BC that was recorded by Chinese and Korean astronomers of the time to have been visible for seventy days. Modern historians place Jesus' birthdate between 7 and 2 BC.
And why December 25? Many feel that Jesus was born in spring or fall and that the December date simply extended the pagan tradition of commemorating the winter solstice, the day on which the sun is farthest south and thus the shortest day of the year. Recently this is occurring on December 21 or 22, but in ancient Rome it fell on the 25th. Their festival, Saturnalia, was dedicated to Saturn, their God of Agriculture. Other aspects of our modern celebration also relate more to pagan than Christian rites: Christmas trees, Yule logs, bells, candles and gifts, for example. In any case the Gospel of Luke tells us that at the time of Jesus' birth "shepherds were abiding in the fields," and sheep are confined to shelters in Bethlehem winters.
Matthew also tells us that those three wise men or magi with the wonderful names, Caspar, Melchior and Balthasar, brought gifts of gold, frankincense and myrrh. We all know what gold is, but those others?
Frankincense is an aromatic resin used for perfumes and, as its name implies, incenses. It is tapped as a milky sap from what one source calls a "very scraggly" Arabian tree of the genus Boswellia. This hardens into what are called tears. Today the best quality frankincense tears are obtained from Oman and Yemen.
Modern medical research suggests the possible use of this resin as a psychoactive drug reducing depression and anxiety. A carefully designed test protocol also showed that a related product called Indian frankincense provided osteoarthritis patients significant relief with no side effects.
Myrrh is another resin. Although it too is burned as incense, it is more often thought of as a traditional medicine for a wide variety of ailments including everything from toothache to uterine tumors. It is the dried sap of sharply spined trees in the genus Commiphora found today in Yemen, Somolia and eastern Ethiopia. (In a quite different context the name myrrh appears in the scientific name for the potherb sweet cicely.)
Today myrrh is used as an antiseptic in liniments and salves for minor wounds and in mouthwashes, gargles and toothpastes for prevention and treatment of gum disease.
One source suggests those gifts served as air fresheners for the stable in which Jesus was born - as Luke so famously tells us: "because there was no room for them in the inn." More likely all three gifts would have been used to buy Jesus' passage to Egypt to escape the subsequent massacre of children by King Herod's troops.-- Gerry Rising